
Yolanda VillacampaUniversity of Alicante | UA · Departamento de Matemática Aplicada
Yolanda Villacampa
Catedrático de Universidad / Full Professor
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Publications (118)
Use of genetic algorithms (GA) in optimization problems is ubiquitous in mathematics [1, 2], engineering [3] and other fields such as economics [4, 5, 6]. In most optimization problems, the solution can be obtained by using numerical approximation techniques derived from the analytical expressions of the conditions on the critical points of a funct...
This study presents a deterministic constrained optimisation algorithm developed for using in a pressurized irrigation network. In irrigation networks-or water networks supplied by a head tank-utility managers can fully adapt the delivery times to suit their needs. The program provides a strategy for scheduling water delivery at a constant flow rat...
Parallel nonlinear models using radial kernels on local mesh support have been designed and implemented for application to real-world problems. Although this recently developed approach reduces the memory requirements compared with other methodologies suggested over the last few years, its computational cost makes parallelisation necessary, especia...
The problem of having ordinary differential equations (ODE) whose coefficients are unknown functions is frequent in several fields. Sometimes, it is possible to obtain samples of the values of these functions in different instants or spatial points. The present paper presents a methodology for the numeric solving of these ODE. There are approximati...
This paper presents a study on the optimization problem of a consumer’s choice constrained to a single time interval. In this problem, the choice is made over a set of perishable goods such that they do not retain value at the end of the period. Money has been introduced as the only means available to store that value for the future. Thus, consumer...
One of the main problems faced in coastal management is the loss or destruction of beaches due to erosion. A considerable diversity of factors is involved in coastal erosion, which makes it a complex system to study. The quality of the material that constitutes the beach, as well as the choice of appropriate materials for its nourishment are two of...
The Pampas region is characterized by a high complexity in its productive system planning and faces the challenge of satisfying future food demands, as well as reducing the environmental impact of the activity. Climate change affects crops and farmers should use species capable of adapting to the changed climate. Among these species, faba bean (Vic...
Solar energy is one of the most promising green energy sources. On-grid photovoltaic installations supply energy to consumers as a support energy source, but in isolated areas, it comes as the unique source. The decision-maker must dimension the installation, maintaining system performance with reasonable investments. In some scenarios, the utility...
In this research, we have shown that the goal of reducing the ecological system to a mathematical model cannot be achieved. Each mathematical model that is built has one of these two drawbacks: either some admissible outputs are not produced or some inadmissible outputs are produced. In this article, the authors aim to clarify to what point natural...
Estimation problems are frequent in several fields such as engineering, economics, and physics, etc. Linear and non-linear regression are powerful techniques based on optimizing an error defined over a dataset. Although they have a strong theoretical background, the need of supposing an analytical expression sometimes makes them impractical. Conseq...
The accurate knowledge of the location and movement of the sand bars is important for the coastal manager to establish correctly the coastal defence elements. This work applies a numerical model of finite elements based on Galerkin's formulation for predicting the location of the start, crest and end of the outer bar. The model that shows the best...
System modeling is a main task in several research fields. The development of numerical models is of crucial importance at the present because of its wide use in the applications of the generically named machine learning technology, including different kinds of neural networks, random field models, and kernel-based methodologies. However, some prob...
En los últimos años, la crisis financiera global y la desaceleración económica que ha castigado a sectores como el de la construcción y obras públicas en España ha supuesto una drástica reducción de la demanda y calidad del alumnado que cursa titulaciones de Ingeniería Civil en todo el país. La investigación propuesta pretende explorar las sinergia...
Depending on the time of development of a crop temperature below 0 °C can cause damage to the plant, altering its development and subsequent yield. Since frosts are identified from the minimum air temperature, the objective of this research paper is to generate forecast -(predictive) models at 1, 3 and 5 days of the minimum daily temperature (Tmin)...
A methodology based on the Galerkin formulation of the finite element method has been analyzed for predicting the compressive strength of the lightweight aggregate concrete using ultrasonic pulse velocity. Due to both the memory requirements and the computational cost of this technique, its parallelization becomes necessary for solving this problem...
Coastal erosion and lack of sediment supply are a serious global problem. It is therefore necessary to determine the depth of closure (DoC) of a beach—key parameter in the calculation of the sand volume and the location of the beach protection elements—in a precise way. For this reason, this work generates a numerical model based on Galerkin's form...
The eigenvalues and eigenvectors of a matrix have many applications in engineering and science, such us studying and solving structural problems in both the treatment of signal or image processing, and the study of quantum mechanics. One of the most important aspects of an algorithm is the speed of execution, especially when it is used in large arr...
Due to the low density of the aggregates used, lightweight aggregate concrete (LWAC) is susceptible to segregation because of the differences between the densities of their components. The segregation in LWAC causes a great variability in the concrete properties causing negative effects in its mechanical properties and durability. Ultrasonic veloci...
Artificial neural networks (ANN) have been widely used successfully to solve coastal engineering problems. In this article, they are used to model the cross-shore profile of sandy beaches taking into account the possible effect of marine vegetation (Posidonia oceanica). Sixty ANNs were generated by modifying both the inputs and the number of neuron...
Spain has traditionally been a country where the coast and beaches have acted as raw material to develop the current tourism industry. This has always led diverse scale works and coastal transformations by Public Administrations in order to satisfy tourist needs and striving to attract a greater number of travelers. However, little and less is know...
This paper presents a model of the cross-shore beach profile taking into account the presence of the seagrass Posidonia oceanica whose ultimate objective is to reduce the volume of sand used in beach nourishment. The methodology describes the training, validation, testing and application of models of artificial neural networks (ANN) for computing t...
The erosion of the world's coasts and the shortage of sand to mitigate beach erosion are leading to the increasingly common use of gravel for coastal protection and beach nourishment. Therefore, in order to determine the amount of gravel required for such actions, it is important to know perfectly the equilibrium profile of gravel beaches. However,...
The paper describes the training, validation, testing and application of models of artificial neural networks (ANN) for computing the cross-shore beach profile of the sand beaches of the province of Valencia (Spain). Sixty ANN models were generated by modifying both the input variables as the number of neurons in the hidden layer. The input variabl...
Monitoring of the quality of bathing water in line with the European Commission bathing water directive (Directive 2006/7/EC) is a significant economic expense for those countries with great lengths of coastline. In this study a numerical model based on finite elements is generated whose objective is partially substituting the microbiological analy...
In this work, numerical models were obtained for describing the segregation phenomenon in lightweight aggregate concrete (LWC). To that end, a numerical methodology based on the generation of geometric models of finite elements has been applied, selecting those that describe better this phenomenon. The use of lightweight aggregate concretes (LWC) a...
Human intervention on the coast has been intense, due to the source of wealth that the coastal areas represent, especially in the form of tourism, which has resulted in a rapid erosion of its beaches. This paper discusses the current state of beach management in the various competent public administrations on the Costa Blanca (SE Spanish-Mediterran...
Numerous studies and theories have emerged for evaluating the quality of beaches using different
parameters. In recent years in the European region, one of the most important aspects when evaluating
a beach is the quality of water and sand. The quality of water is represented by the amount of Intestinal
Enterococcus and Escherichia coli. This param...
Tourism development in recent decades has involved a large urban development in coastal areas, with
different anthropogenic structural interventions on the coast such as the construction of commercial
buildings and marinas, which has led to intense erosion and large imbalances in the last century. This
situation also affects the city of Alicante, w...
This article focuses on the optimal architecture of the neural network for determining the three characteristic points of the bars (starting, crest and final point). For the definition of the network, precision profiles, sedimentological and wave data were used. A total of 209 profiles taken for 22 years was used. The inputs were analysed and selec...
The depth of closure of the beach profile, from now on termed as DoC, is a key parameter to perform effective evaluations of beach nourishments or coastal defence works. It is defined for a given time interval, as the closest depth to the shore at which there is no significant change in seabed elevation and no significant net sediment transport bet...
The study of equilibrium profile is a fundamental concept in beach morphodynamics and necessary in the design of nourishment. For this reason, it is important to introduce new modelling methodologies that are capable of analysing its behaviour. The aim of the research was to generate mathematical models for obtaining parameter A of the potential fu...
In this paper, mathematical models for obtaining the parameter A of the potential function, which describes the equilibrium beach profile, were generated. The aim of the research was to analyse the most important variables related to the equilibrium beach profile, so that the models are used only those variables that are easy to obtain. On the othe...
Human intervention on the coast has been intense, due to the source of wealth that the coastal areas represent, especially in the form of tourism, which has resulted in a rapid erosion of its beaches. This paper discusses the current state of beach management in the various competent public administrations on the Costa Blanca (SE Spanish-Mediterran...
Tourism development in recent decades has involved large urban development in coastal areas, with different anthropogenic structural interventions on the coast such as the construction of commercial buildings and marinas, which led to intense erosion and large imbalances in the last century. This situation also affects the city of Alicante, with th...
Numerous studies and theories have emerged for evaluating the quality of beaches using different parameters. In recent years in the European region one of the most important aspects when evaluating a beach is the quality of water and sand. The quality of water is represented by the amount of Intestinal Enterococcus and Escherichia coli. This parame...
The great scientific interest in the gravel beaches is due to the growing use of coarse materials in the nourishment of eroded sand beaches. The objective of this research is to obtain a model for an equilibrium profile of gravel beaches, which has been divided into the three parts of the transverse profile: Profile in the backshore, intermediate p...
The new methods accurately integrate forced and damped oscillators. A family of analytical functions is introduced known as T-functions which are dependent on three parameters. The solution is expressed as a series of T-functions calculating their coefficients by means of recurrences which involve the perturbation function. In the T-functions serie...
The eigenvalues and eigenvectors of a matrix have many applications in engineering and science. For example they are important in studying and solving structural problems, in the treatment of signal or image processing, in the study of quantum mechanics and in certain physical problems. It is therefore essential to analyze methodologies to obtain t...
A new classification of microtidal sand and gravel beaches with very different morphologies is presented below. In 557 studied transects, 14 variables were used. Among the variables to be emphasized is the depth of the Posidonia oceanica. The classification was performed for 9 types of beaches: Type 1: Sand and gravel beaches, Type 2: Sand and grav...
Aragonés, L.; López, I.; Villacampa, Y.; Serra, J.C., and Saval, J.M., 2015. New methodology for the classification of gravel beaches: Adjusted on Alicante (Spain). In this article, a methodology is presented for the classification of gravel beaches, which can be applied internationally. Such beaches' defence against the energy of incoming water fl...
Mathematical models used for the understanding of coastal seabed morphology play a key role in beach nourishment projects. These projects have become the fundamental strategy for coastal maintenance during the last few years. Accordingly, the accuracy of these models is vital to optimize the costs of coastal regeneration projects. Planning of such...
The mechanical resistance to penetration in agricultural soils varies with the water content of the soil. Therefore the variation of soil humidity may mask the differences between treatments which were in the process of being evaluated. One way to avoid this problem is to make a correction in the humidity content of the soil. The aim of this study...
Bahía Norte, located in Alicante, is an artificial coastal area that suffers from erosion, which disturbs the environment, the life and the economy of surrounding areas. In order to mitigate the erosion problem, a solution that provides coastal improvements and allows users to enjoy the structure is proposed. This solution develops artificial surfi...
In this article, a new methodology is presented to obtain representation models for a priori relation z=u(x"1,x"2,...,x"n) (1), with a known an experimental dataset z"i,x"i^1,x"i^2,x"i^3,...,x"i^n"i"="1","2","...","p. In this methodology, a potential energy is initially defined over each possible model for the relationship (1), what allows the appl...
The aim of the project is to determine if the understanding of the language of Mathematics of students starting university is propitious to the development of an appropriate cognitive structure. The objective of this current work was to analyse the ability of first-year university students to translate the registers of verbal or written expressions...
Higher education should provide the acquisition of skills and abilities that allow the student to play a full and active role in society. The educational experience should offer a series of conceptual, procedural and attitudinal contents that encourage "learning to know, learning to do, learning to be and learning to live together". It is important...
The interest to improve the response of structures in front of an earthquake has increased in recent years, leading to the investigation of different calculation methods, especially those based on static non-linear analysis to increase accuracy. The non-linear calculation can be approached by means of discrete or continuous models. The discrete mod...
The determination of the leaf area of plants is important in studies related to their
growth and development because in the leaves are synthesized the carbohydrates
that will be distributed to the other organs of the plant. In this paper, the authors
want to apply new modeling methodologies and compare them with the usual
techniques to obtain infor...
In this paper, the different variables that characterize the soybean crop in
Argentina are analyzed. The main objective is to obtain information that will be
useful for the analysis of the environmental consequences of the progress of this
crop in the country.
This has been made by a descriptive statistical analysis and a factor analysis
was used t...
The study of natural systems implies considering new modelling methodologies
that are able to produce different relationships to those described with
mathematical functions, which are derived from the geometry of Euclid.
In this paper, the authors propose a geometric model defined by families of
cubic Splines, which are the basis for a definition o...
In the Flooding Pampas, Argentina, as agricultural expansion spread into areas
historically used for livestock grazing, it came to occupy the best soils in the
area. The need therefore arose to increase the production of forage species able
to adapt to increasingly stressed soil conditions.
Lotus tenuis is an exotic leguminous forage plant that has...
The literature states that project duration is affected by various scope factors. Using 168 building projects carried out in Spain, this paper uses the multiple regression analysis to develop a forecast model that allows estimating project duration of new builds. The proposed model uses project type, gross floor area (GFA), the cost/GFA relationshi...
In this article a new methodology is developed, for the modelling of complex systems where the number of variables and relationships can be high. This methodology allows an efficient work on a n-dimensional hypercube and its computational implementation, a fact that was not possible through a generalisation of the 2-dimensional methodology develope...
After the deindustrialization process of Europe many buildings and complexes were abandoned and their activities were moved out of the cities due to the growth of urban centres. One of those locations is Bovisa in the North of Milan, where old structures of former factories are standing near contemporary buildings. Furthermore, as a common characte...
This article presents a new multi-step numerical method based on φ-function series and designed to integrate forced oscillators with precision. The new algorithm retains the good properties of the MDFpPC methods while presenting the advantages of greater precision and that of integrating the non-perturbed problem without any discretization error. I...
Energy efficiency is becoming one of the key paths to transforming the South
African economy into low carbon growth. This vision has been accepted by both
the government and business community. To this end, the White Paper on
Energy, National Energy Efficiency Strategy of 2005 (revised 2008), Energy
Efficiency Accord and the National Climate Change...
Considering the soil as a complex, dynamic and heterogeneous system, chaos
theory is a useful tool for gaining new knowledge into its variability. Fractal
geometry has a close relationship with chaos theory, which describes dynamic
and chaotic events with a development in time and space that can be predicted
probabilistically. Furthermore, the conc...
In order to maintain a reasonable standard of living and comfort, society is
dependent on using very high levels of energy. The challenge is to pursue
sustainable development while maintaining the level of activity, transformation
and progress in every productive sector. In this paper, the influence of every
parameter that determinates the energy r...
There are several ways of implementing a PV systems networking site,
depending on the income that you would like to achieve. Fixtures can be built
with solar tracking axis and two axes solar tracking. In this work we make a
detailed comparative study of the implementation of a solar photovoltaic
installation in a particular place, the three systems...
El proyecto tiene como objetivo la planificación de contenidos, materiales y metodologías docentes, de acuerdo con el Espacio Europeo de Enseñanzas Superiores, del Segundo Curso del Grado en Arquitectura para el curso 2011/12. Para ello han formado parte del trabajo los profesores que podrán ser coordinadores/as de las asignaturas y estarán implica...
This article creates a new method for the numerical integration of forced and damped oscillators, and their computational implementation. It also provides a generalisation of methods based on G-function and φ-function series.The algorithm produced in this paper integrates the non-perturbed problem with no truncation error, in which the perturbation...
This paper examines an Information Storage System (ISS), in which a vocabulary and set of experimental data are defined, on the basis of which both linear and linearized (meaning that they are treated in linear fashion) mathematical models are generated. The studies obtained lead to establish certain objective criteria that let us select the best c...
Y. Villacampa1, F. J. Navarro-González1 & J. Llorens2
1Departamento de Matemática Aplicada, Universidad de Alicante, Spain
2Departamento de Sistemas Informático y Computación,
Universidad Politécnica de Valencia, Spain
Abstract
When studying and modelling Complex Systems where there can be a
considerable number of variables and relations, it is ver...
N-fixing legume crops may be a good component of a general plan to improve
cropping system efficiency. For this purpose, crop suitability to specific
environments must be established. Irrigated field experiments were conducted
for three years (2004–2007) with cv. ‘Alameda’ sown on five different dates in
each year.
This article examines the phenolo...
Lotus glaber Mill, a diploid forage legume (2n=2x=12), has successfully adapted
to the ecological characteristics of the Flooding Pampas region of the Province
of Buenos Aires, Argentina. This species is highly valued, basically due to its
ability to adapt to soils that do not allow other forage legumes to prosper, as well
as for its high nutrition...
Foliar area and light penetration are two variables that have a major impact on production. The former gives an idea of the potential photosynthetic capacity of the plant, while the latter indicates the amount of light received by its different strata. In 1952, Watson introduced the Leaf Area Index (LAI) concept, which is defined as the sum of the...